CVE-2026-50243 Affecting libunbound8 package, versions <1.25.2-160000.1.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.1% (1st percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-SLES1600-LIBUNBOUND8-19287895
  • published27 Aug 2026
  • disclosed10 Aug 2026

Introduced: 10 Aug 2026

CVE-2026-50243  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 libunbound8 to version 1.25.2-160000.1.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libunbound8 package and not the libunbound8 package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

In NLnet Labs Unbound 1.6.2 up to and including 1.25.1, when Unbound is configured with the 'respip' module in front of the validator together with a 'response-ip' redirect rule or an RPZ file with an RPZ-IP trigger, the rewriting handler does not check the security status of the upstream answer and can instead rewrite a BOGUS A/AAAA answer to point to an operator's configured IP. If the validator finds an expired or otherwise invalid RRSIG on an answer whose A record falls within a 'response-ip'/RPZ configuration, the answer is still rewritten and given a hard coded security level of INSECURE. This results in the client receiving an INSECURE NOERROR reply rewritten by the operator's configured IP. A malicious actor can exploit the possible poisonous effect by spoofing a BOGUS A/AAAA answer that falls inside the operator's configured subnet rewrites. Such DNSSEC protected answers are then insecurely redirected to the operator's configured target.

CVSS Base Scores

version 3.1